Centrifugal fan and air conditioner having the same

ABSTRACT

A centrifugal fan, which equally maintains air-blowing capacities of both inlets regardless of different suction resistances of both inlets due to a driving device, and an air conditioner having the centrifugal fan. The centrifugal fan includes a rotary plate; first blades disposed at the edge of one surface of the rotary plate; and second blades disposed at the edge of the other surface of the rotary plate, and having a larger outer diameter than the outer diameter of the first blades. Thus, although a large flow resistance is generated at one inlet of the centrifugal fan due to the driving device, air-blowing capacities of both inlets are maintained equally.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 2008-0100387, filed on Oct. 13, 2008, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

The present invention relates to a centrifugal fan and an air conditioner having the same, and more particularly to a bidirectional centrifugal fan, which sucks fluid in both directions, and an air conditioner having the same.

2. Description of the Related Art

In general, a centrifugal fan forcibly blows fluid, which is sucked in the axial direction, in the centrifugal direction by the rotation of blades. Such a centrifugal fan is used in an air conditioner requiring a large amount of air.

In order to increase the amount of air sucked and blown in both directions, i.e., the right and left directions, a bidirectional suction type centrifugal fan (hereinafter, referred to as a bidirectional centrifugal fan), in which two centrifugal fans are connected into a single fan type, has been proposed.

The bidirectional centrifugal fan includes a plurality of blades at each of both sides of a rotary plate, to which a rotary shaft of a driving motor is connected, to suck air in both directions, i.e., the right and left directions, and thus is capable of blowing a large amount of air, compared with a unidirectional centrifugal fan, which sucks air in one direction.

However, since the driving motor is installed at any one of inlets at both sides of the bidirectional centrifugal fan, one inlet with the driving motor generates larger flow resistance of the fluid than the other inlet without the driving motor.

Due to a difference of channel structures between both inlets, the conventional bidirectional centrifugal fan having the equal outer diameter of outlets causes the deterioration of an air-blowing capacity at the inlet with the driving motor.

Further, air flown into the inlet with the driving motor and air flown into the inlet without the driving motor are exhausted and mixed at the outlets of the bidirectional centrifugal fan. At this time, the states of both the discharged fluids are different, and thus, an air-blowing loss is generated and noise and vibration are increased during the mixing process of the two fluids.

SUMMARY

Therefore, one aspect of the invention is to provide a centrifugal fan, which equally maintains air-blowing capacities of both inlets regardless of different suction resistances of both inlets due to a driving device, and an air conditioner having the centrifugal fan.

Another aspect of the invention is to provide a centrifugal fan, which minimizes an air-blowing loss during mixing two air flows discharged through outlets regardless of different suction resistances of both inlets, and an air conditioner having the centrifugal fan.

A further aspect of the invention is to provide a centrifugal fan, which has a bidirectional suction structure to reduce noise and vibration, and an air conditioner having the centrifugal fan.

In accordance with one aspect, the present invention provides an air conditioner including a rotary plate; first blades disposed at the edge of one surface of the rotary plate; and second blades disposed at the edge of the other surface of the rotary plate, and having a larger outer diameter than the outer diameter of the first blades.

The height of the second blades may be larger than the height of the first blades.

The inner diameter of the first blades may be smaller than the inner diameter of the second blades.

The outer diameter of the first blades may be smaller than the diameter of the rotary plate.

The first blades and the second blades may be respectively disposed in a ring shape at the edges of the surfaces of the rotary plate.

In accordance with another aspect, the present invention provides an air conditioner including a rotary plate; and a pair of first and second inlets disposed in opposite to each other in the axial direction of the rotary plate such that air is sucked to the centrifugal fan in both directions, wherein the suction region of the second inlet is wider than the suction region of the first inlet.

The centrifugal fan may further include a pair of first and second outlets in the radial direction of the rotary plate, and the discharge region of the second outlet may be wider than the discharge region of the first outlet.

The centrifugal fan may further include a first shroud connected to the outer edges of the first blades and a second shroud connected to the outer edges of the second blades, and the outer diameter of the second shroud may be larger than the outer diameter of the first shroud.

In accordance with a further aspect, the present invention provides an air conditioner, which has a centrifugal blowing unit to forcibly blow air, the centrifugal blowing unit including a centrifugal fan including a rotary plate; first blades disposed at the edge of one surface of the rotary plate; and second blades disposed at the edge of the other surface of the rotary plate, and having a larger outer diameter than the outer diameter of the first blades; and a driving device disposed at the second blades to provide rotary force to the rotary plate.

The rotary plate may be connected directly to a rotary shaft of the driving device.

The height of the second blades may be larger than the height of the first blades.

The inner diameter of the first blades may be smaller than the inner diameter of the second blades.

Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a longitudinal-sectional view illustrating the schematic appearance of an air conditioner in accordance with an embodiment of the present invention;

FIG. 2 is a perspective view of a centrifugal fan of the air conditioner in accordance with an embodiment of the present invention; and

FIG. 3 is a longitudinal-sectional view of the centrifugal fan taken along line of FIG. 2.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to embodiments of the present invention, an example of which is illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below to explain the present invention by referring to the annexed drawings.

FIG. 1 is a longitudinal-sectional view illustrating the schematic appearance of an air conditioner in accordance with an embodiment of the present invention, FIG. 2 is a perspective view of a centrifugal fan of the air conditioner in accordance with an embodiment of the present invention, and FIG. 3 is a longitudinal-sectional view of the centrifugal fan taken along line III-III of FIG. 2.

The air conditioner in accordance with the embodiment, as shown in FIG. 1, includes a heat exchanger 11 installed in the upper portion of the inside of a main body 10, and a centrifugal blowing unit 20 installed in the lower portion of the inside of the main body 10.

The main body 10 is provided with side suction ports 12 a respectively formed through both the side surfaces thereof to suck indoor air therethrough, a rear suction port 12 b formed through the rear surface thereof, side discharge ports 13 respectively formed through both sides of the upper portion thereof, and a front discharge port 14 formed through the center of the front surface thereof. An upper door 15 to open and close the front discharge port 14 is installed on the upper portion of the front surface of the main body 10. The upper door 15 is installed such that the upper door 15 ascends and descends along rails (not shown) formed on the main body 10, and an ascent and descent device 16 to ascend and descend the upper door 15 is installed on the rear surface of the upper door 15.

The heat exchanger 11 in the main body 10 is formed as a flat panel type such that air blowing upward from the centrifugal blowing unit 20 can exchange heat with the heat exchanger 11, and is inclined such that the upper surface of the inside of the main body 10 is divided by the heat exchanger 11.

The centrifugal blowing unit 20, as shown in FIG. 1, includes a fan casing 21, a centrifugal fan 30 installed in the fan casing 21, and a driving device 40 to drive the centrifugal fan 30. The driving device 40 is fixed to the inner surface of the rear surface of the main body 10, and the centrifugal fan 30 is connected to a rotary shaft 41 extended from the driving device 40 to the inside of the fan casing 21.

The fan casing 21 includes a first suction port 22 and a second suction port 23 respectively formed through the front and rear surfaces thereof to suck air, and a discharge port 24 formed through the upper surface thereof to discharge air. The structure allows air, sucked to the inside of the fan casing 21 through the first and second suction ports 22 and 23, to be discharged to the outside of the fan casing through the discharge port 24 by the operation of the centrifugal fan 30.

The fan casing 21 may include a scroll type diffusion pattern, in which an inner channel 25 is gradually diffused close to the discharge port 24. This structure serves to gradually increase an inner channel area in the flowing direction of air. Further, the fan casing 21 is configured such that the uppermost portion of the diffusion pattern of the fan casing 21 is divided from the discharge port 24 to split an air flow, and this configuration corresponds to the general structure of the fan casing and thus a detailed description thereof will be omitted.

The centrifugal fan 30, as shown in FIGS. 1 to 3, is a bidirectional centrifugal fan, which sucks air through first and second suction ports 22 and 23 formed through the front and rear surfaces of the fan casing 21, i.e., in both directions. The centrifugal fan 30 includes a rotary plate 31 connected to the rotary shaft 41, a plurality of first blades 32 fixed to the outer circumference of one surface 31 b of the rotary plate 31, a plurality of second blades 33 fixed to the outer circumference of the other surface 31 c of the rotary plate 31, a ring-shaped first shroud 34 connected to the outer edges of the first blades 32, and a ring-shaped second shroud 35 connected to the outer edges of the second blades 33.

The rotary plates 31 is provided with a rotary shaft connection hole 31 a, to which the rotary shaft 41 of the driving device 40 is connected, formed through the center thereof, and is formed in a disk shape to divide a flow of fluid, sucked into the centrifugal fan 30 in both directions when the centrifugal fan 30 is driven.

Thus, the rotary plate 31 and the first blades 32 disposed in a ring shape on the surface 31 b of the rotary plate 31 form a first inlet 36 along the axial direction of the centrifugal fan 30, and form a first outlet 37 along the radial direction of the centrifugal fan 30.

Further, the rotary plate 31 and the second blades 33 disposed in a ring shape on the surface 31 c of the rotary plate 31 form a second inlet 38 along the axial direction of the centrifugal fan 30, and form a second outlet 39 along the radial direction of the centrifugal fan 30.

The driving device 40, for example, a motor, is disposed at the second inlet 38 of the centrifugal fan 30, and the rotary shaft 41 of the driving device 40 is inserted into the rotary shaft connection hole 31 a of the rotary plate 31.

Since the driving device 40 is disposed at the second inlet 38, the second inlet 38 generates a larger suction resistance than the first inlet 36, and thus the capacity of the surface 31 c of the rotary plate 31 with the second inlet 38 and the second outlet 39 may be lower than the capacity of the surface 31 b of the rotary plate 31.

Further, air sucked through the first inlet 36 and air sucked through the second inlet 38 are not mixed in the centrifugal fan 30, but are mixed after the air sucked through the first inlet 36 and the air sucked through the second inlet 38 are respectively discharged through the first and second outlets 37 and 39. When the flowing states of the air discharged through the first outlet 37 and the air discharged through the second outlet 39 are different, a loss is generated during a process of mixing both the discharged air flows.

Therefore, the embodiment proposes a structure, which maintains flow resistances of the air sucked through the first inlet 36 and the air sucked through the second inlet 38 equally or similarly, although a unit generating a flow resistance is installed at one side of the centrifugal fan 30, and thus improves the performance of the centrifugal fan 30.

For this reason, in the centrifugal fan 30 of the embodiment, the first blades 32 are disposed in a ring shape at the edge of the surface 31 b of the rotary plate 31 and the second blades 33 are disposed in a ring shape having a larger outer diameter (A) than the outer diameter (B) of the first blades 32 at the edge of the surface 31 c of the rotary plate 31.

That is, in consideration of the flow resistance generated by the driving device 40 disposed at the second inlet 38, the outer diameter (A) of the second blades 33 is larger than the outer diameter (B) of the first blades 32 such that the suction region of the second inlet 38 is larger than the suction region of the first inlet 36.

The optimum values of the outer diameters of the first and second blades 32 and 33 to allow the air sucked through the first inlet 36 and the air sucked through the second inlet 38 to have the substantially equal or similar flow resistance(s) are obtained from experiments based on flow resistances according to the size and position of the driving device 40 disposed at the second inlet 38.

Further, the optimum value of the relation between the diameter of the rotary plate 31 and the outer diameters of the first and second blades 32 and 33 is obtained also from experiments. In this embodiment, for example, the outer diameter of the second blades 33 corresponds to the diameter of the rotary plate 31, and the outer diameter of the first blades 32 is smaller than the diameter of the rotary plate 31.

Even in a case where the driving device 40 is mounted at a position of the centrifugal fan 30 adjacent to the second inlet 38, the outer diameter of the second blades 33 is larger than the outer diameter of the first blades 32 and the suction region of the second inlet 38 is larger than the suction region of the first inlet 36, and thus the flow resistances of air flows respectively sucked through both sides of the centrifugal fan 30 are maintained substantially equally or similarly, in spite of the increase of the flow resistance by the driving device 40.

Further, the height (D) of the second blades 33 is larger than the height (C) of the first blades 32.

Through the above configuration, the discharge region of the second outlet 39 is larger than the discharge region of the first outlet 37, and thus the second outlet 39 is capable of discharging air more efficiently than the first outlet 37.

The first blades 32 have an inner diameter (E) smaller than the inner diameter (F) of the second blades 33. The inner diameter (E) of the first blades 32 becomes smaller than the inner diameter (F) of the second blades 33 by causing the first and second blades 32 and 33 to have the same width (G).

In this embodiment, exemplarily, the first blades 32 and the second blades 33 have the same width (G). However, the first and second blades 32 and 33 may have various widths, and the optimum values of the widths of the first and second blades 32 and 33 may be obtained from experiments.

The first shroud 34 is connected to the outer edges of the first blades 32, and has an outer diameter, which is smaller than the diameter of the rotary plate 31.

The second shroud 35 is connected to the outer edges of the second blades 33, and has an outer diameter, which is larger than the outer diameter of the first shroud 34.

In the above-described bidirectional centrifugal fan 30 of the embodiment, the outer diameter (A) of the second blades 33 is larger than the outer diameter (B) of the first blades 32, and thus the flow resistances of the air flows sucked through the first and second inlets 36 and 38 are maintained substantially equally or similarly although the driving device 40 to drive the centrifugal fan 30 is located at the second inlet 38 of the centrifugal fan 30. Thereby, the bidirectional centrifugal fan 30 of the embodiment has an improved air-blowing capacity, compared with a conventional centrifugal fan.

Further, in the above structure, the height (D) of the second blades 33 is larger than the height (C) of the first blades 32, and thus the blowing properties of the air flows discharged through the first and second outlets 37 and 39 are maintained substantially equally or similarly. Thereby, it is possible to minimize an air-blowing loss generated during a process of mixing the air flows respectively discharged through the first and second outlets 37 and 39, and to reduce noise and vibration.

Although this embodiment describes that the outer diameter of the first blades of the centrifugal fan is equal to that of the blades of a conventional centrifugal fan and the outer diameter of the second blades of the centrifugal fan is larger than that of the blades of the conventional centrifugal fan, the outer diameter of the second blades of the centrifugal fan may be equal to that of the blades of the conventional centrifugal fan and the outer diameter of the first blades of the centrifugal fan may be smaller than that of the blades of the conventional centrifugal fan by a designated degree.

Further, although this embodiment describes that the rotary shaft of the driving device is connected directly to the rotary shaft insertion hole of the rotary plate, pulleys may be respectively installed at the rotary shaft of the motor and the rotary shaft insertion hole of the rotary plate and a belt may be connected to both the pulleys to transmit the rotary force of the motor to the centrifugal fan. The centrifugal blowing unit having the above configuration may have different flow resistances at the first and second inlets due to the mounting of the pulleys and the belt at one side of the centrifugal fan.

Moreover, although this embodiment describes that the centrifugal fan is installed in an air conditioner, the centrifugal fan may be applied to various apparatuses, which require a bidirectional centrifugal fan, such as a ventilating apparatus as well as the air conditioner.

As described above, the centrifugal fan in accordance with the example embodiment includes a pair of blades having different outer diameters such that the inlet with the driving device is larger than the inlet without the driving device, and thus maintains flow resistances of air sucked through the first and second inlets substantially equally or similarly, thereby improving an air-blowing capacity compared with a conventional centrifugal fan.

Further, the centrifugal fan in accordance with the example embodiment causes the second blades to have a height larger than the height of the first blades in the above structure, thereby minimizing an air-blowing loss generated during a process of mixing air flows discharged through the first and second outlets and reducing noise and vibration.

Although embodiments of the invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A centrifugal fan comprising: a rotary plate; first blades disposed at the edge of one surface of the rotary plate; and second blades disposed at the edge of the other surface of the rotary plate, and having a larger outer diameter than the outer diameter of the first blades.
 2. The centrifugal fan according to claim 1, wherein the height of the second blades is larger than the height of the first blades.
 3. The centrifugal fan according to claim 1, wherein the inner diameter of the first blades is smaller than the inner diameter of the second blades.
 4. The centrifugal fan according to claim 1, wherein the outer diameter of the first blades is smaller than the diameter of the rotary plate.
 5. The centrifugal fan according to claim 4, wherein the first blades and the second blades are respectively disposed in a ring shape at the edges of the surfaces of the rotary plate.
 6. A centrifugal fan comprising: a rotary plate; and a pair of first and second inlets disposed in opposite to each other in the axial direction of the rotary plate such that air is sucked to the centrifugal fan in both directions, wherein the suction region of the second inlet is wider than the suction region of the first inlet.
 7. The centrifugal fan according to claim 6, further comprising a pair of first and second outlets in the radial direction of the rotary plate, wherein the discharge region of the second outlet is wider than the discharge region of the first outlet.
 8. The centrifugal fan according to claim 7, further comprising a first shroud connected to the outer edges of the first blades and a second shroud connected to the outer edges of the second blades, wherein the outer diameter of the second shroud is larger than the outer diameter of the first shroud.
 9. An air conditioner, which has a centrifugal blowing unit to forcibly blow air, the centrifugal blowing unit comprising: a centrifugal fan including a rotary plate; first blades disposed at the edge of one surface of the rotary plate; second blades disposed at the edge of the other surface of the rotary plate, and having a larger outer diameter than the outer diameter of the first blades; and a driving device disposed at the second blades to provide rotary force to the rotary plate.
 10. The air conditioner according to claim 9, wherein the rotary plate is connected directly to a rotary shaft of the driving device.
 11. The air conditioner according to claim 9, wherein the height of the second blades is larger than the height of the first blades.
 12. The air conditioner according to claim 10, wherein the inner diameter of the first blades is smaller than the inner diameter of the second blades. 